Activated carbon - Superb Adsorption

Activated carbon, also called activated charcoal, is a form of carbon processed to have small, low-

volume pores that increase the surface area available for adsorption or chemical reactions. Activated is sometimes replaced by active. Due to its high degree of microporosity, one gram of activated carbon has a surface area in excess of 3,000 m² (32,000 sq ft) as determined by gas adsorption. An activation level sufficient for useful application may be obtained solely from a high surface area. Further chemical treatment often enhances adsorption properties.

Activated charcoal, also known as activated carbon is commonly produced from high carbon sources materials such as wood or coconut husk. It is made by treating the source material with either a combination of heat and pressure or with a strong acid or base followed by carbonization to make it highly porous. This gives it a very large surface area for its volume, up to 3000 square meters per gram. It has a large number of industrial uses including methane and hydrogen storage, air purification, decaffeination, gold purification, metal extraction, water purification, medicine, sewage treatment, and air filters in gas masks and respirators.

Activated carbon is usually derived from charcoal. When derived from coal it is referred to as activated coal. Activated coke is derived from coke.

Properties

A gram of activated carbon can have a surface area in excess of 500 m² (5,400 sq ft), with 3,000 m² (32,000 sq ft) being readily achievable.

Under an electron microscope, the high surface-area structures of activated carbon are revealed. Individual particles are intensely convoluted and display various kinds of porosity; there may be

many areas where flat surfaces of graphite-like material run parallel to each other, separated by only a few nanometers or so. These micropores provide superb conditions for adsorption to occur, since adsorbing material can interact with many surfaces simultaneously. Tests of adsorption behavior are usually done with nitrogen gas at 77 K under high vacuum, but in everyday terms activated carbon is perfectly capable of producing the equivalent, by adsorption from its environment, liquid water from steam at 100 °C (212 °F) and pressure of 1/10,000 of an atmosphere. Activated carbon can be used as a substrate for the application of various chemicals to improve the adsorptive capacity for some inorganic (and problematic organic) compounds such as hydrogen sulfide (H₂S), ammonia (NH₃), formaldehyde (HCOH), mercury (Hg) and radioactive iodine-131(¹³¹I). This property is known as chemisorption.

Production

Activated carbon is carbon produced from carbonaceous source materials such as bamboo, coconut husk, willow peat, wood, coir, lignite, coal, and petroleum pitch. It can be produced by one of the following processes:

1. Physical activation: The source material is developed into activated carbon using hot gases. Air is then introduced to burn out the gasses, creating a graded, screened, and de-dusted form of activated carbon. This is generally done by using one or more of the following processes:
   • Carbonization: Material with carbon content is pyrolyzed at temperatures in the range of 600–900 °C, usually in an inert atmosphere with gases like argon or nitrogen
   • Activation/Oxidation: Raw material or carbonized material is exposed to oxidizing atmospheres (oxygen or steam) at temperatures above 250 °C, usually in the temperature range of 600–1200 °C.
2. Chemical activation: The carbon material is impregnated with certain chemicals. The chemical is typically an acid, strong base, or a salt (phosphoric acid 25%, potassium hydroxide 5%, sodium hydroxide 5%, calcium chloride 25%, and zinc chloride 25% ). The carbon is then subjected to higher temperatures (250–600  °C). It is believed that the temperature activates the carbon at this stage by forcing the material to open up and have more microscopic pores. Chemical activation is preferred to physical activation owing to the lower temperatures, better quality consistency, and shorter time needed for activating the material.

Mitigate Climate change and Save a life

Environmental

Carbon adsorption has numerous applications in removing pollutants from air or water streams both in the field and in industrial processes such as:

• Spill cleanup
• Groundwater remediation
• Drinking water filtration
• Air purification
• Volatile organic compounds capture from painting, dry cleaning, gasoline dispensing operations, and other processes
• Volatile organic compounds recovery (solvent recovery systems, SRU) from flexible packaging, converting, coating, and other processes.

We have seen activated carbon can be the very best environmental solution for purification and cleaning up

air from toxic and unwanted residue. It works to adsorption the air was very efficient. Some companies made a shift by new innovation with saving environment mindset to design a new and modern product, to mitigate climate change, without using any electric power and only as standalone modern with new design product, can change the air from bad to better. It has been tested and effective to eliminate the covid19 variant in the air.

Agricultural

Activated carbon (charcoal) is an allowed substance used by organic farmers in livestock production. In livestock production, it is used as a pesticide, animal feed additive, processing aid, nonagricultural ingredient, and disinfectant. 

Medical use

Activated charcoal is used to detoxify people, but only in life-threatening medical emergencies such

as overdoses or poisonings. As it is indigestible it will only work on poisons or medications still present in the stomach and intestines. Once these have been absorbed by the body the charcoal will no longer be able to adsorb them so early intervention is desirable. Charcoal is not an effective treatment for alcohol, metals, or elemental poisons such as lithium or arsenic as it will only absorb certain chemicals and molecules. It is usually administered by a nasogastric tube into the stomach as the thick slurry required for maximum adsorption is very difficult to swallow.